1. Field of the Invention
The present invention deals with the field of alarms and sensing systems for noting an excess amount of carbon monoxide or a low amount of oxygen with any closed environment. With the widespread use of automatic garage door openers a problem has arisen concerning some owners who will mistakenly warm up the engines of motor vehicles within garages wherein the door operators are closed. In this manner a lethal environment can be created within a closed chamber adjacent a dwelling or the like.
The present system provides the means for sensing the lack of oxygen or an excess amount of carbon monoxide within a garage in order to automatically open a garage door. Such sensing devices have problems heretofore untreated such as when a car is started and the door is immediately opened sometimes an amount of carbon monoxide can travel in the area of the sensor which will cause the door to immediately open once it is closed after the driver has left the location which will allow the door to remain open throughout the day until the driver returns. This problem is overcome by the present invention by the use of a delay clock. Whenever the door is opened a limit switch will sense this opening action and initiate the five minute delay clock which will prevent opening of the door by the gas detection means for five minutes after any door opening operation. Therefore any fumes which have gathered in the area of the gas detection means when a driver backs his car out of the garage and then closes the door will not cause the door to be instantly opened but will delay for five minutes and only at the end of the five minute time period will the door be caused to open if the carbon monoxide is still localized in the area of the gas detection means.
2. Description of the Prior Art
Various emergency gas alarms and sensing systems are shown in the prior art such as U.S. Pat. Nos. 3,641,541; 3,757,471; 3,777,423; and 3,908,309. These condition-responsive sensing systems do not suggest usage with an automatic door opener which is the particular application of the present invention.
U.S. Pat. No. 3,908,309 does show a system for sensing the products of combustion for responsively controlling door entries into the chamber. However, none of the prior art suggests or appreciates the problems created by automatic sensing systems usable with automatic door operator devices.